Harness motion for loom



Jan. 16, 1962 w. Y. ROBB 3,016,923

HARNESS MOTION FOR LOOM Filed June 1-0, 1960 2 Sheets-Sheet 1 INVENTOR WALTER Y ROBB ATTORNEY WMTM Jan. 16, 1962 w. Y. ROBB 3,016,923.

HARNESS MOTION FOR LOOM Filed June 10, 1960 2 Sheets-Sheet 2 INVENTOR WALTER Y. ROBB ATTORNEY United States Patent 3,015,923 Patented Jan. 16, 1962 3,016,923 HARNE MQTION FOR LOOM Walter Y. Robb, Whitinsviile, Mass, assignor to Crampton 81 Knowles Corporation, Worcester, Mass., a corporation of Massachusetts Filed June 10, 1960, Ser. No. 35,242 8 Claims. (Cl. 139-46) This invention relates to improvements in harness motions more particularly for pile fabric looms.

In certain types of looms the pile yarns are raised and lowered by a harness frame which lifts the pile yarns from a low position to a high position Where a shogging mechanism shifts the pile yarn laterally over pile wires, after which the pile harness frame lowers the pile yarns to the starting position. The present trend of the floor covering industry is to make carpets at a high rate of speed with a row of tufts for each weft inserted into the weave, or for each shedding operation of the ground warps, and the present invention aims to comply with this trend.

The ground warps are controlled by harness frames at least one of which rises from a low position to a high position on one heat of the loom and then returns from high position to the low position on the next beat of the loom, at least one other frame moving oppositely. The harness frames for the ground weave are required to have but one motion in one direction for each weft inserting operation of the loom. Attempts have been made to operate the pile harness frame from the same shaft or at least in time with the cams which operate the ground warps, but it has been found that such a mode of operation requires such steep slopes for the cam of the pile harness frame as to interfere seriously with eflicient production. If the cam for the pile harness frame is secured to the same shaft which turns the cams for the ground warps the loom must be operated at a low rate in order to avoid breakage and excess strains.

It is an important object of the present invention to modify the cam for the pile harness frame and its drive in such manner that the cam can be made without steep slopes, thus enabling the loom to operate at a commercially acceptable speed.

It is another object of the invention to rotate the pile harness operating cam at a rate faster than the rate at which the ground warp cams operate, the faster rate preferably being a multiple of the rate at which the ground warp operating cams rotate. In this way the active surface of the pile harness operating cam can be spread over a larger angular area and a smoother mode of operation attained.

It is another object of the invention to mount the pile harness operating cam means loosely on the cam or primary shaft of the loom and then by means of gearing cause the loose cam to rotate faster than does the cam shaft. This result is attained as set forth hereinafter and as employed on a loom built according to the present invention by providing a secondary shaft which is driven from the cam shaft but at a faster rate and then causing the secondary shaft to rotate the pile harness operat ing cam. As set forth hereinafter, a sprocket and chain mechanism between the cam shaft and the secondary shaft causes the latter to operate at a rate which is a multiple of the rate of the cam shaft, and other chain and sprocket mechanism between the secondary shaft and the pile harness operating cam causes the latter to operate at said multiple rate.

In order that the invention may be clearly understood reference is made to the accompanying drawings which illustrate by way of example the embodiments of the invention and in which:

FIG. 1 is a plan view of part of a pile fabric loom having the invention applied thereto,

FIG. 2 is a vertical section on line 22, FIG. 1, on an enlarged scale, and

FIG. 3 is a side elevation of one of the ground warp harness operating cams and its lever.

Referring to FIGS. 1 and 2, the loom frame F comprises right and left loomsides 1 and 2 respectively between which extend several cross members such as the right and left-hand cross girts 3 and 4 as shown more particularly in FIG. 2, a cross support 5 for a cloth board 6, a cross member 7 for the pile wires to be described, another cross member 3, and a crosswise rod 9 shown at the upper right-hand part of FIG. 2. These parts are all stationary and together with other parts not specifically shown herein constitute the rigid part of the loom frame.

The loom is provided with a primary cam shaft ltl mounted in suitable bearings and have secured to each end thereof a pair of ground warp harness frame operating cams all of which are similar to the cam 11 shown in FIG. 3 except for their setting on the shaft. These cams are keyed to the shaft, and in the present instance they are set in such manner as to cause one-half of the ground warp to be rising while the other half is descending during loom operation.

The cross girt 3 pivotally supports harness frame operating levers 12 which are pivotally mounted at 13 in a bearing 14- secured to the rear cross girt 3. These levers are operatively connected to the harness frames 15 and 16 which operate the two sets of ground warp threads W1 and W2 which form the ground weave of the fabric being woven. A weft laying needle N at the upper left hand part of FIG. 2 is of the kind customarily employed on axminster looms and operates with an outside package filling supply not shown herein.

The cross member 7 supports a number of pile wires 20 which extend longitudinally of the warp threads and are clamped by a bar 21 against a back plate 22 by means of bolts, one of which is shown at 23. Bolts 24, one of which is shown herein, secures the back plate 22 to the cross member 7. Each pile wire has an upwardly :extending part 25 the upper end of which may, if desired, be formed with a slight rise 26 and has also a forwardly extending part 27 which extends over a part at least of the cloth board 6. The pile wires are stationary and form the piles in the fabric to be woven. The lay designated generally at L is of usual construction and is driven to give the reed 30 a forward beat, to the left in FIG. 2, after each insertion of weft by the needle N.

Referring more particularly to FIG. 3 which is representative of the cams which operate the ground warp threads, it will be seen that the cam has two low dwells 35 and 36 and two high dwells 37 and 38 joined by inclines one of which is designated at 39.

The driving mechanism for the loom (not shown) is geared to the primary shaft 10 in such manner as to rotate this shaft once for each four insertions of weft by the needle N. This is not a necessary relation so far as certain aspects of the invention are concerned but that type of drive has been applied to a loom operating according to this invention. It will be seen in FIG. 3 that the rise of the cam 11 appears between lines a and b defining an angle 0. It is to be understood that the ground warp harness frames 15 and 16 will shift in one direction on one beat of the loom and in the opposite direction on the next beat of the loom and that the vertical motion of the harness frame is determined by the part of the cam represented by angle 0.

The matter thus far described is of more or less usual which is trained a chain 54 meshing with a relatively large sprocket wheel 55. The latter sprocket is fastened to the primary shaft 10 so that for each rotation of the primary shaft the secondary shaft makes four rotations. An idler sprocket 56 for tightening chain 54 is mounted on bearing 57 supported from the cross girt 8. There is a single chain 54 and a set of associated parts as will be understood from FIG. 1.

Secured to the secondary shaft 51 are two sprocket wheels 60 one on either side of the chain 54 and these sprockets are connected by chains 61 to sprocket wheels 62 each of which is fastened to a cam 63. FIG. 1 shows two of the chains 61 and sets of associated parts, but if desired on wider looms other chains 61 can be added.

The cam 63 has a dwell 65, a decline 66, a short dwell 6'7, and an incline 68. Cam 63 is of the groove type and receives a roll 70 on a lever 71 which is pivoted at 13. The forward end of each of the levers 71 is attached by a connector 72 to the lower part of the pile harness frame 50. In FIG. 2, for the sake of clearness, these connectors are indicated diagrammatically as are also the connectors 73 for the ground harness frames 15 and 16. Diagonal braces 75 connected to cross girt 4 and cross rod 9 support idler sprocket wheels 76 used to take up slack in chains 61.

During operation each of the earns 63 will have a complete rotation for each weft laying stroke of the needle and each beat of the lay so that the lever 71 for each of these cams will rise due to decline 66, and will have a slight dwell to hold the harness frame up while a pile yarn shogging or shifting mechanism 73 moves laterally to shift the pile yarn over the pile wires, after which lever 71 will then descend due to incline 68. For the remainder of the rotation of cam 63 the harness frame 50 will remain down below the needle so that the pile warp designated at PW can be caught by the weft laid by the needle.

The purpose of the cams 63 will be apparent from FIG. 3 Where it will be seen that the angle is too small to permit a full up motion of the harness frame, a slight dwell in high positiomand then a full down motion. Prior to the present invention attempts were made to accomplish this complete reciprocation of the harness frame bycams secured to the primary shaft 10 but the slope of the inclines and declines were so steep as to require theloom to run at a slow speed, too slow for efficient operation. By having the cams 63 complete a rotation for each pick of the loom the decline 66 and incline 68 canv be made more gradual than would be possible otherwise and the loom can be made to operate at efficient speeds.

As an example, the invention has been utilized on a 16/ 4 to have a smooth rise and fall motion and does not in.

any way interfere with desired speeds of operation.

From the foregoing it will be seen that the invention sets forth simple means by which the slope of the inclines on the pile harness operating cam having been reduced to an extent which permits commercial rate of operation of the loom while permitting the cams which operate the ground warps to operate at their usual speed. This result is attained by connections between the primary or'cam shaft and the pile harness operating cam means so designed as to turn the latter at a faster rate than the ground operating cams turn, this faster rate preferably being a multiple of'the rate at which the ground warp operating cams turn. The specific form of the invention shown herein produces four warp sheds in the ground warps for'each rotation of the cam or primary shaft and the pile harness operating cam means is turned at a rate four times that of the cam shaft, but this specific speed ratio isnotthe only one at which the invention can be operated; It is desirable that the loose cam means operate at least twice as fast as the cams which operate the ground warps.

Having now particularly described and ascertained the nature of the invention and in what manner the same is to be performed, what is claimed is:

1. In a pile fabric loom operating with stationary pile wires and ground warps, a pile warp harness frame which upon a complete reciprocation lifts pile warps from a low position to a high position above the pile wires for shifting of the pile warps transversely over the pile wires, and then lowers the pile warps to said low position, rotary cams effective during a rotation thereof to form different sheds in the ground warps, cam means effective when rotated to cause a reciprocation of the pile harness frame, and operative connections between the rotary cams and the cam means causing the latter to rotate at a rate which is a multiple of the rate of rotation of the rotary cams to effect reciprocation of the pile harness frame.

2. In a pile fabric loom operating with stationary pile wires and ground warps, a pile warp harness frame which upon a complete reciprocation lifts pile warps from a low position to a high position above the pile wires or shifting the pile warps transversely over the pile wires, and then lowers the pile warps to said low position, pile harness operating lever means, a shaft rotating at a given rate during loorn operation, ground Warp cams secured to the shaft effective to cause the ground warps to form different sheds in the ground warps for each rotation of the shaft, cam means operatively connected to the lever means effective on a rotation thereof to cause the lever means to effect a reciprocation of the pile harness frame, and connections between the shaft and said cam means causing the latter to rotate at a rate which is a multiple of said given rate and rotate once for each shed formed in the ground warps by the ground warp cams.

3. In a pile fabric loom operating with stationary pile wires and ground warps, a pile warp harness frame which reciprocates vertically to lift pile waips from a low position on one side of the pile wires to a high position, higher than the pile wires and then descends to return the pile warps on the other side of the pile wires to said low posi: tion, a primary shaft having cams thereon effective to cause the ground warps to form at least two successive different sheds for each rotation of the primary shaft, a.

secondary shaft, rotary pile harness operating cam means driven from the secondary shaft effective to reciprocatethe pile harness frame once for each rotation of the, cam means, and operative driving connections between the shafts and cam means causing the latter to rotate once for each shed formed in the ground warps by the cams.

wheels of unequal size and a chain connect the shaftsand equal sprockets and chain connect the secondary shaft and cam means.

7. The loom set forth in claim 3 wherein the, primary shaft drives the secondary shaft and the secondary shaft is in driving relation with the pile harness cam means.

8. The loom set forth in claim 7 wherein the primary shaft causes the secondary shaft to rotate once for each shed formed in the ground warps and the driving relation between the secondary shaft and the pile cam: means causes the latter to rotate once for each rotation of the secondary shaft.

References Cited in the file of this patent UNITED STATES PATENTS 2,868,231 Robb Jan. 13, 1959 

